Disk-like nanoparticles

ABSTRACT

A disk-like nanoparticle includes a core layer that comprises a cross-linked multi-vinyl substituted aromatic hydrocarbon and a shell layer that comprises tri-block copolymer chains, each having a first, a second, and a third block. The first and third blocks of the tri-block copolymer chains comprise vinyl aromatic monomer units and are crosslinked with the core. The second block comprises conjugated diene monomer units and comprises a top and bottom axial surface of the disk-like nanoparticle. In the case of a nanoparticle having A-B-C tri-block copolymer chains, the third block comprises a top and bottom axial surface of the disk-like nanoparticle.

This application is a continuation of U.S. application Ser. No.12/288,174, filed on Oct. 17, 2008, which, in turn is acontinuation-in-part of U.S. application Ser. No. 12/184,895, filed Aug.1, 2008, which, in turn, is a continuation-in-part of U.S. applicationSer. No. 11/641,514, published as U.S. 2007/0149649, filed Dec. 19,2006, which, in turn, claims the benefit of U.S. Provisional ApplicationNo. 60/751,602, filed Dec. 19, 2005. Each of these applications areincorporated herein by reference.

SUMMARY AND BACKGROUND

The present disclosure is generally related to polymer nanoparticles.More particularly, the present disclosure provides polymer nanoparticlescomprising tri-block copolymer chains that form a particular formationor shape.

Over the past several years, polymer nanoparticles have attractedincreased attention not only in the technical fields such as catalysis,combinatorial chemistry, protein supports, magnets, and photonics, butalso in the manufacture of rubbery products such as tires. For example,nanoparticles can modify rubbers by uniformly dispersing throughout ahost rubber composition as discrete particles. The physical propertiesof rubber such as moldability and tenacity can often be improved throughsuch modifications. Moreover, some polymeric nanoparticles may serve asa reinforcement material for rubber. For example, polymer nano-stringsare capable of dispersing evenly throughout a rubber composition, whilemaintaining a degree of entanglement between the individualnano-strings, leading to improved reinforcement over traditionalreinforcing fillers.

However, an indiscriminate addition of nanoparticles to rubber may causedegradation of the matrix rubber material. Rather, very careful controland selection of nanoparticles having suitable architecture, size,shape, material composition, and surface chemistry, etc., are needed toimprove the rubber matrix characteristics. For example, properties ofpolymeric nanoparticles made from diblock copolymer chains arecontrolled by the thermodynamics of diblock copolymers in a selectedsolvent. The thermodynamic phase diagram of those systems usuallydepends on two factors, the volume fractions of the components (Φ_(i),i=1, 2, 3 . . . ) and the miscibility between them (χ_(ij)N_(i)parameter between components). Therefore, for a given system, i.e., whenthe χ_(ij)N_(i) parameters between components are fixed, the formationof micelle structures depends primarily on the volume fraction of eachcomponent (Φ_(i), i=1, 2, 3 . . . ). In order to obtain a micellenanoparticle of desired structure, the concentration or the volumefraction must be controlled. Flexibility of concentration adjustment isusually small due to the underlying thermodynamic laws and the phasediagrams. As such, it cannot provide high flexibility in concentrationvariations. This could raise unwelcome constraints in industrialprocesses.

Advantageously, the present disclosure provides a disk-like nanoparticleincluding a core layer that comprises a cross-linked multi-vinylsubstituted aromatic hydrocarbon and a shell layer that comprisestri-block copolymer chains, each having a first, a second, and a thirdblock. The first and third blocks of the tri-block copolymer chainscomprise a vinyl aromatic monomer and are crosslinked with the core. Thesecond block comprises a conjugated diene monomer units and comprisesthe top and bottom axial surfaces of the disk-like nanoparticle. Theweight ratio of the monomer comprising the first block and third blockto the monomer comprising the second block is 1:1 to 100:1.

A rubber composition comprising a rubber matrix and the disk-likenanoparticle disclosed above is also provided. A tire comprising therubber composition is also described herein.

A method for making a disk-like nanoparticle in a liquid hydrocarbonmedium is also provided. The nanoparticle has a core layer and a shelllayer, the shell layer comprises tri-block copolymer chains having afirst block, a second block, and a third block. The method comprises thesteps of: polymerizing conjugated diene monomers with a multi-functionallithiated amine containing initiator, wherein the initiator is ahydrocarbon solvent soluble, anionic polymerization multi-lithio amineinitiators that comprises at least two or more lithio amines in onemolecule and has the general formula:

wherein Q is (a) an element selected from the group consisting of O, S,N, P and Si or (b) an alkylene group having from 1 to 20 methylenegroups, and R₁ and R₂ are the same or different and are selected fromthe group consisting of alkyls, cycloalkyls and aralkyls containing from1 to 20 carbon atoms; copolymerizing vinyl aromatic monomers to form thefirst and third blocks, thereby producing the tri-block copolymerchains; assembling the tri-block copolymer chains in the liquidhydrocarbon medium to form micelle structures; and crosslinking amultiple-vinyl-substituted aromatic hydrocarbon with the tri-blockcopolymer chains in the micelle structures to form a cross-linked coreand to form polymer nanoparticles.

A disk-like nanoparticle produced from the method described above isalso presented.

In another embodiment, a disk-like nanoparticle includes a core layercomprising a cross-linked multi-vinyl substituted aromatic hydrocarbon,and a shell layer comprising A-B-C tri-block copolymer chains, eachhaving a first, a second, and a third block. The first block of theA-B-C tri-block copolymer chains includes a vinyl aromatic monomer andis crosslinked with the core. The second block includes a conjugateddiene monomer, and the third block comprises the top and bottom axialsurfaces of the disk-like nanoparticle. The disk-like nanoparticlefurther includes a residue of a multi-functional lithiatedamine-containing initiator, wherein the initiator is a hydrocarbonsolvent soluble, anionic polymerization multi-lithio amine initiatorsthat comprises at least two or more lithio amines in one molecule andhas the general formula:

wherein Q is (a) an element selected from the group consisting of O, S,N, P and Si or (b) an alkylene group having from 1 to 20 methylenegroups, divalent and R₁ and R₂ are the same or different and areselected from the group consisting of alkyls, cycloalkyls and aralkylscontaining from 1 to 20 carbon atoms.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings are only for purposes of illustrating embodiments and arenot to be construed as limiting the invention. In the drawings appendedhereto:

FIG. 1 illustrates two possible conformations of a tri-block copolymerchain in polymer nanoparticles;

FIG. 2 is a transmission electron microscopy (TEM) photograph of polymernanoparticles with controlled architecture of a tree-like dendrite;

FIG. 3 is a TEM photograph of polymer nanoparticles with controlledarchitecture of a nano-rope;

FIG. 4 is a TEM photograph of polymer nanoparticles with controlledarchitecture of a nano-sphere with flower-like inner structure;

FIG. 5 is a TEM photograph of polymer nanoparticles with architecture ofsphere, chain, dumbbell and other irregular structures;

FIG. 6 is a TEM photograph of polymer nanoparticles with architecture ofshort nano-ropes;

FIG. 7 is a TEM photograph of polymer nanoparticles with architecture ofshort nano-sized branches;

FIG. 8 is a TEM photograph of polymer nanoparticles with architecture ofa short nano-sized branch;

FIG. 9 is a TEM photograph of polymer nanoparticles with architecture ofnarrowly distributed nano-sized branches;

FIG. 10 is a TEM photograph of polymer nanoparticles with architectureof narrowly distributed nano-sized branches;

FIG. 11 is an illustration of a cross-sectional view of a disk-likenanoparticle comprising A-B-A tri-block copolymer chains;

FIG. 12 is an illustration of a cross-sectional view of a disk-likenanoparticle comprising A-B-C tri-block copolymer chains;

FIG. 13 is a TEM photograph of a collection of disk-like nanoparticles;

FIG. 14 is a second TEM photograph of the collection of disk-likenanoparticles;

FIG. 15 is a TEM photograph of a second collection of disk-likenanoparticles;

FIG. 16 is a second TEM photograph of the second collection of disk-likenanoparticles;

FIG. 17 is a TEM photograph of a third collection of disk-likenanoparticles; and

FIG. 18 is a TEM photograph of a fourth collection of disk-likenanoparticles with an illustration showing how the disk-like particlesare overlapped.

DETAILED DESCRIPTION

It is to be understood herein, that if a “range” or “group” is mentionedwith respect to a particular characteristic of the present invention,for example, molecular weight, ratio, percentage, chemical group, andtemperature etc., it relates to and explicitly incorporates herein eachand every specific member and combination of sub-ranges or sub-groupstherein whatsoever. Thus, any specified range or group is to beunderstood as a shorthand way of referring to each and every member of arange or group individually as well as each and every possible sub-rangeor sub-group encompassed therein; and similarly with respect to anysub-ranges or sub-groups therein. Furthermore, the terms “a” and “the,”as used herein mean “one or more.”

In an embodiment, non-spherical polymer nanoparticles are formed fromtri-block copolymer chains of the following formula (I):

wherein A comprises a conjugated diene monomer; B comprises a vinylaromatic monomer; a is an integer of from 1 to 100,000 and b₁≈b₂ andeach of them is an integer of from 1 to 100,000, such as from 1 to10,000.

By b₁≈b₂, it is intended that the value Δ calculated from the followingequation ranges from 0 to 20%, such as from 0 to 10%, or from 0 to 5%.

$\Delta = {\frac{{b_{1} - b_{2}}}{b_{1} + b_{2}} \times 100\%}$

For simplicity, the terms of “Block α”, “Block β”, and “Block γ” arehereinafter used to denote the three blocks of the tri-block copolymerrespectively as shown below:

The tri-block copolymers and the polymer nanoparticles are formedthrough living anionic polymerization, although emulsion polymerizationmay also be contemplated. The method of synthesis can be a multi-stageanionic polymerization. Multi-stage anionic polymerizations have beenconducted to prepare block-copolymers, for example in U.S. Pat. No.4,386,125, which is incorporated herein by reference. Other relevantpublications include U.S. Pat. Nos. 6,437,050 and 6,875,818, and U.S.Patent Application 2005/0154117, all of which are incorporated herein byreference.

The nanoparticles are formed from tri-block copolymer chains comprisingBlock α, Block β, and Block γ. Living blocks such as blocks α and blocksγ may be crosslinked with a multiple-vinyl-substituted aromatichydrocarbon to form the desired polymer nanoparticles. The polymernanoparticles may retain their discrete nature with little or nopolymerization between each other. The nanoparticles can besubstantially monodisperse and uniform in shape.

According to one embodiment, a tri-block copolymer is formed of vinylaromatic hydrocarbon monomer and conjugated diene monomer in ahydrocarbon medium. The liquid hydrocarbon medium functions as thedispersion solvent, and may be selected from any suitable aliphatichydrocarbons, alicyclic hydrocarbons, or mixture thereof, with a provisothat it exists in liquid state during the nanoparticles' formationprocedure. Exemplary aliphatic hydrocarbons include, but are not limitedto, pentane, isopentane, 2,2 dimethyl-butane, hexane, heptane, octane,nonane, decane, and the like. Exemplary alicyclic hydrocarbons include,but are not limited to, cyclopentane, methyl cyclopentane, cyclohexane,methyl cyclopentane, cycloheptane, cyclooctane, cyclononane,cyclodecane, and the like. These hydrocarbons may be used individuallyor in combination. In one embodiment, the liquid hydrocarbon medium ishexane.

In one embodiment, the polymerization of monomers into the tri-blockcopolymer is initiated via addition of divalent anionic initiators thatare known in the art as useful in the copolymerization of diene monomersand vinyl aromatic hydrocarbons. Such initiators can be selected fromorganic compounds comprising two lithium groups as represented by theformula as shown below:Li—R—Li

wherein R is a hydrocarbon group having 2 valences. R generally contains4 to 30 carbon atoms per R group.

In a variety of exemplary embodiments, a bi-functional anionic initiatormay have a general formula (L) as shown below:

in which R₁ is hydrogen or methyl; and R₂ includes aliphatic radicalsand cycloaliphatic radicals, such as alkyl, cycloalkyl, cycloalkylalkyl,alkylcycloalkyl, alkenyl, as well as aryl and alkylaryl radicals.Specific examples of R₂ groups include, but are not limited to, alkylssuch as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl,sec-butyl, n-amyl, isoamyl, n-hexyl, n-octyl, n-decyl, and the like;cycloalkyls and alkylcycloalkyl such as cyclopentyl, cyclohexyl,2,2,1-bicycloheptyl, methylcyclopentyl, dimethylcyclopentyl,ethylcyclopentyl, methylcyclohexyl, dimethylcyclohexyl, ethylcyclohexyl,isopropylcyclohexyl, 4-butylcyclohexyl, and the like; cycloalkylalkylssuch as cyclopentyl-methyl, cyclohexyl-ethyl, cyclopentyl-ethyl,methyl-cyclopentylethyl, 4-cyclohexylbutyl, and the like; alkenyls suchas vinyl, propenyl, and the like; arylalkyls such as 4-phenylbutyl;aryls and alkylaryls such as phenyl, naphthyl, 4-butylphenyl, p-tolyl,and the like.

For example, R₁ and R₂ in formula (L) can be methyl and sec-butylrespectively; and the bi-functional anionic initiator has the formula(L-1) as shown below:

The formula (L-1) bi-functional anionic initiator may be prepared, forexample, according to the following reaction:

Other bi-functional anionic initiators include, but are not limited to,1,4-dilithiobutane, 1,5-dilithiopetane, 1,10-dilithiodecane,1,20-dilithioeicosane, 1,4-dilithiobenzene, 1,4-dilithionaphthalene,1,10-dilithioanthracene, 1,2-dilithio-1,2-diphenylethane, and the like,and mixtures thereof.

The bi-functional anionic initiator may be used singly, or may becombined with additional bi-functional anionic initiators to initiatethe polymerization of conjugated diene monomers A into Block β. Itshould be understood that typically the bi-functional anionic initiatorresidue is present in approximately the central region of Block β. Forexample, an exemplary living block β may be represented as shown below:

Any suitable conjugated diene or mixture thereof may be used as monomerA and be polymerized into Block β via the bi-functional anionicinitiator. For example, the conjugated diene may be selected fromconjugated 1,3-diene monomer represented by the formula (II) as shownbelow:

in which R₅, R₆, R₇, and R₈ are each independently selected from thegroup consisting of hydrogen, methyl, ethyl, propyl, and isopropyl.

Specific examples of the conjugated diene monomers A include, but arenot limited to, 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), cis-and trans-piperylene (1,3-pentadiene), 2,3-dimethyl-1,3-butadiene,1,3-pentadiene, cis- and trans-1,3-hexadiene, cis- andtrans-2-methyl-1,3-pentadiene, cis- and trans-3-methyl-1,3-pentadiene,4-methyl-1,3-pentadiene, 2,4-dimethyl-1,3-pentadiene, and the like, andthe mixture thereof. In certain embodiments, 1,3-butadiene, isoprene, orcombination thereof are used as the conjugated diene monomer A.

The polymerization of conjugated diene monomers A into Block β may lastas long as necessary until the reaction is completed and a desireddegree of polymerization, i.e. “a” in Formula (I), is obtained. Thepolymerization reaction of this step may last typically from 0.1 hoursto 10 hours, such as from 0.2 hours to 8 hours, or from 0.2 hours to 4hours. In exemplified embodiments, the polymerization reactions of thisstep lasted 1.5 hours.

The anionic polymerization to form Block β may be conducted in thepresence of a modifier or a 1,2-microstructure controlling agent, so asto, for example, increase the reaction rate, equalize the reactivityratio of monomers, and/or control the 1,2-microstructure in theconjugated diene monomers A. Suitable modifiers include, but are notlimited to, triethylamine, tri-n-butylamine, hexamethylphosphoric acidtriamide, N, N, N′, N′-tetramethylethylene diamine, ethylene glycoldimethyl ether, diethylene glycol dimethyl ether, triethylene glycoldimethyl ether, tetraethylene glycol dimethyl ether, tetrahydrofuran,1,4-diazabicyclo[2.2.2]octane, diethyl ether, tri-n-butylphosphine,p-dioxane, 1,2 dimethoxy ethane, dimethyl ether, methyl ethyl ether,ethyl propyl ether, di-n-propyl ether, di-n-octyl ether, anisole,dibenzyl ether, diphenyl ether, dimethylethylamine, bix-oxalanylpropane, tri-n-propyl amine, trimethyl amine, triethyl amine,N,N-dimethyl aniline, N-ethylpiperidine, N-methyl-N-ethyl aniline,N-methylmorpholine, tetramethylenediamine, oligomeric oxolanyl propanes(OOPs), 2,2-bis-(4-methyl dioxane), bistetrahydrofuryl propane, and thelike.

In certain embodiments, the anionic polymerization to form Block β canbe conducted in the presence of an amine compound such as triethylamine, trimethyl amine, tripropyl amine, tri-isopropyl amine,tri-n-butyl amine, and the like, and the mixtures thereof.

Other modifiers or 1,2-microstructure controlling agents used may belinear oxolanyl oligomers represented by the structural formula (IV) andcyclic oligomers represented by the structural formula (V), as shownbelow:

wherein R₁₄ and R₁₅ are independently hydrogen or a C₁-C₈ alkyl group;R₁₆, R₁₇, R₁₈, and R₁₉ are independently hydrogen or a C₁-C₆ alkylgroup; y is an integer of 1 to 5 inclusive, and z is an integer of 3 to5 inclusive.

Specific examples of modifiers or 1,2-microstructure controlling agentsinclude, but are not limited to, oligomeric oxolanyl propanes (OOPs);2,2-bis-(4-methyl dioxane); bis(2-oxolanyl)methane;1,1-bis(2-oxolanyl)ethane; bistetrahydrofuryl propane;2,2-bis(2-oxolanyl)propane; 2,2-bis(5-methyl-2-oxolanyl)propane;2,2-bis-(3,4,5-trimethyl-2-oxolanyl)propane;2,5-bis(2-oxolanyl-2-propyl)oxolane;octamethylperhydrocyclotetrafurfurylene (cyclic tetramer);2,2-bis(2-oxolanyl)butane; and the like. A mixture of two or moremodifiers or 1,2-microstructure controlling agents may also be used.

The vinyl aromatic monomers B include, but are not limited to styrene,α-methyl-styrene, 1-vinyl naphthalene, 2-vinyl naphthalene, vinyltoluene, methoxystyrene, t-butoxystyrene, and the like; as well asalkyl, cycloalkyl, aryl, alkaryl, and aralkyl derivatives thereof, inwhich the total number of carbon atoms in the monomer is generally notgreater than 18; and mixtures thereof. In exemplified embodiments, thevinyl aromatic monomer B comprises styrene.

Copolymerizing vinyl aromatic monomers B with the living block β startsat both living ends of Block β. Block α and Block γ may thus be formedin two directions, obtaining a tri-block copolymer comprising Block α,Block β, and Block γ, as shown in Formula (I).

Without being bound to any theory, it is believed that Block β is moresoluble or miscible in a selected liquid hydrocarbon medium than Blocksα and γ, facilitating the subsequent micelle-like assembling andnanoparticle formation from the tri-block copolymer chains comprisingBlock α, Block β, and Block γ.

Depending on their miscibility, polymer chains in solution or suspensionsystem can be self-assembled into domains of various structures. Withoutbeing bound to any theory, it is believed that a micelle-like structuremay be formed by aggregating the tri-block copolymer chains comprisingBlock α, Block β, and Block γ. Blocks α and γ are typically directedtoward the central region of the micelle and Blocks β are typicallyextended away from the center.

Without being bound to any theory, it is believed that a tri-blockcopolymer chain comprising Block α, Block β, and Block γ may exist intwo conformations. With reference to FIG. 1, the first possibleconformation may be called a “looped” conformation, in which thetri-block copolymer chain 001 is looped and Block α and Block γ aredirected toward the central region 002 of a micelle and Block β isextended away from the central region 002. The second possibleconformation may be called “extended” conformation, in which thetri-block copolymer chain 003is extended and Block α and Block γ aredirected toward two central regions (004 and 005) of two micelles; andBlock β may function as a bridge between the two central regions.

Without being bound to any theory, it is believed that a tri-blockcopolymer chain comprising Block α, Block β, and Block γ may be used toadjust the interactions between micelle-like structural domains. Assuch, the teachings of this disclosure can not only be used toselectively manipulate the interactions between formed micelles, butalso take advantage of the self-assembly thermodynamics of copolymerchains in a selected solvent. For example, a tri-block copolymer chainmay behave like a bridge between micelles, if Block β is sufficientlylong. Thus, the formation of randomly linked tree-like micelles can beused for making nano-dendrites by adding a multiple-vinyl-substitutedaromatic hydrocarbon such as divinyl benzene (DVB) to “freeze” thestructure. Changing the size of the bridge can alter the physical forcesbetween micelles. As a result, the change in physical forces canreconstruct the micelle structures, e.g., from two micelles to acylinder, and then from several cylinders to a nano-sized chain or rope.If the bridge size is sufficiently small, the nano-assembly of polymerchains can change to spherical particles of flower-like innerstructures.

In a variety of exemplary embodiments, di-block polymers may optionallybe combined and/or polymerized with the tri-block copolymer chainscomprising Block α, Block β, and Block γ, to effectively createassembling chains and build varieties of particle shapes. Such di-blockcopolymers may be comprised of a conjugated diene block and a vinylaromatic hydrocarbon block. Suitable conjugated diene monomers and vinylaromatic hydrocarbon monomers are those identified above. In certainembodiments, the di-block copolymers include styrene-isoprene,styrene-butadiene or styrene-SBR di-block polymers. Non-sphericalpolymeric nanoparticles may be constructed not only based on theself-assembly thermodynamics of tri-block and optionally di-blockcopolymers in selected solvents, but also based on the selectivemanipulation of interactions between formed micelles.

Any suitable multiple-vinyl-substituted aromatic hydrocarbon or mixturethereof may be used to copolymerize with Blocks α and Blocks γ of thetri-block copolymers, and optionally the vinyl aromatic hydrocarbonblock of the di-block copolymer, in the micelle structures, andcrosslink them to form polymeric nanoparticles. In certain embodiments,the multiple-vinyl-substituted aromatic hydrocarbon has a higheraffinity with the vinyl aromatic hydrocarbon blocks of the tri-block anddi-block copolymers. As such, the multiple-vinyl-substituted aromatichydrocarbon is able to migrate to the center of the micelle-likestructures, and crosslink the center core of the micelle to form thepolymer nanoparticles. Consequently, the non-spherical polymericnanoparticles are formed from the micelle-like structures with a coremade from multiple-vinyl-substituted aromatic hydrocarbons, a shell madefrom the conjugated diene blocks, and a layer made from the vinylaromatic hydrocarbon blocks, which lies between the core and the shell.

In certain embodiments, the tri-block copolymer chain(s) are in“extended” conformation, as illustrated in FIG. 1, and may function toconnect two or more micelle-like structures. Therefore, Block β iscalled “bridge” in certain embodiments. Bridge size may be characterizedby, for example, the value a in formula (I), molecular weight (Mw or Mn)of Block β, or length of Block β, among others.

The multiple-vinyl-substituted aromatic hydrocarbons can be representedby the formula below:

in which p is an integer and 2≦p≦6, such as 2 or 3, e.g.di-vinyl-benzene (DVB).

In certain embodiments, the divinyl benzene may be selected from any oneof the following isomers or any combination thereof:

In copolymerizing multiple-vinyl-substituted aromatic hydrocarbons withthe vinyl aromatic hydrocarbon blocks of the tri-block and optionallydi-block copolymers in the micelle structures to form polymernanoparticles, the copolymerization time for this step may lasttypically from 0.1 hours to 24 hours, such as from 0.1 hours to 10hours, or from 0.4 hours to 8 hours.

The process of preparing the polymer nanoparticles may be conducted at atemperature of from −70° F. to 350° F., such as from 25° F. to 300° F.,or from 100° F. to 200° F. In exemplified embodiments, a reactor wasequipped with external jacket, which was heated to a temperature around130° F.

The polymerization reactions used to prepare the polymer nanoparticlesmay be terminated with a terminating agent. Suitable terminating agentsinclude, but are not limited to, alcohols such as methanol, ethanol,propanol, and isopropanol; amines, MeSiCl₃, Me₂SiCl₂, Me₃SiCl, SnCl₄,MeSnCl₃, Me₂SnCl₂, Me₃SnCl, and etc. In certain embodiments, theterminating agent may optionally contain an antioxidant such asbutylated hydroxytoluene (BHT).

In the following five sections, specific conditions for the preparationof nanoparticles with controlled architectures of tree-like dendrite,nano-rope, nano-sphere with flower-like inner structure, nano-branch,and nano-disks will be described in detail.

(I) Tree-Like Dendrite

In certain embodiments, the controlled architecture of the polymernanoparticle is in the shape of tree-like dendrite. The term “tree-like”dendrite is meant to encompass structures comprising a both longer andshorter “branches”, similar to the structure of a tree. The meandiameter of the tree-like dendrite nanoparticle may be broadly withinthe range of from 5 nm to 100 microns, in another embodiment within therange of from 10 nm to 50 microns, and in a further embodiment withinthe range of from 100 nm to 5 microns

In preparing the tree-like dendrite nanoparticles, the number averagemolecular weight (Mn_(β)) of Block β may be controlled within the rangeof from 19.5K to 35K, and in another embodiment within the range of from22K to 30K, and in another embodiment within the range of from 24K to27K. In certain embodiments, Mn_(β)≈25K.

In preparing the tree-like dendrites, the number average molecularweight (Mn_(α)) of Block α is approximately equal to the number averagemolecular weight (Mn_(γ)) of Block γ, i.e. Mn_(α)≈Mn_(γ). In certainembodiments, Mn_(α) or Mn_(γ) may be controlled within the range of from20K to 50K, in another embodiment within the range of from 25K to 45K,and in a further embodiment within the range of from 30K to 40K. Incertain embodiments, Mn_(α)≈Mn_(γ)≈35K.

(II) Nano-Rope

In some embodiments, the controlled architecture of the polymernanoparticle is in the shape of a nano-rope. The mean diameter of thenano-rope nanoparticle may be broadly within the range of from 1 nm to200 nm, in another embodiment within the range of from 5 nm to 100 nm,in a further embodiment within the range of from 5 nm to 80 nm, and inyet another embodiment within the range of from 5 nm to 50 nm. Thelength of the nano-rope may be broadly within the range of from 0.1 μmto 200 μm, in another embodiment within the range of from 0.5 μm to 50μm, and in another embodiment within the range of from 1 μm to 10 μm.

In preparing the nano-ropes, the number average molecular weight(Mn_(β)) of Block β may be controlled within the range of from 11.5K to19.5K, in another embodiment within the range of from 13K to 16K, and ina further embodiment within the range of from 13.5K to 15K. In certainembodiments, Mn_(β)≈14K. In preparing the nano-ropes, the number averagemolecular weight (Mn_(α)) of Block α is approximately equal to thenumber average molecular weight (Mn_(γ)) of Block γ, i.e. Mn_(α)≈Mn_(γ).In a variety of exemplary embodiments, Mn_(α) or Mn_(γ) may becontrolled within the range of from 20K to 50K, alternatively within therange of from 25K to 45K, and in another embodiment within the range offrom 30K to 40K. In certain embodiments, Mn_(α)≈Mn_(γ)≈35K.

(III) Nano-Spheres with Flower-Like Inner Structure

In some embodiments, the controlled architecture of the polymernanoparticle is in the shape of nano-spheres with flower-like innerstructure. The mean diameter of the spheres may be broadly within therange of from 1 nm to 500 nm, in another embodiment within the range offrom 1 nm to 200 nm, in another embodiment within the range of from 1 nmto 100 nm, and in yet another embodiment within the range of from 5 nmto 80 nm.

In preparing the nano-spheres with flower-like inner structure thenumber average molecular weight (Mn_(β)) of Block β may be controlledwithin the range of from 5K to 11.5K, alternatively within the range offrom 7K to 10K, and in another embodiment within the range of from 8K to10K. In certain embodiments, Mn_(β)≈9K.

In preparing the nano-spheres with flower-like inner structure, thenumber average molecular weight (Mn_(α)) of Block α is approximatelyequal to the number average molecular weight (Mn_(γ)) of Block γ, i.e.Mn_(α)≈Mn_(γ). In certain embodiments, Mn_(α) or Mn_(γ) may becontrolled within the range of from 20K to 50K, in another embodimentwithin the range of from 25K to 45K, and in another embodiment withinthe range of from 30K to 40K. In certain embodiments, Mn_(α)≈Mn_(γ)≈35K.

(IV) Nano-Branch

In some embodiments, the controlled architecture of the polymernanoparticle is in the shape of nano-branch. The mean diameter of thenano-branch may be broadly within the range of from 1 nm to 200 nm, inanother embodiment within the range of from 5 nm to 100 μm, in a furtherembodiment within the range of from 5 nm to 80 micron, and in yetanother embodiment within the range of from 5 nm to 50 micron.

In preparing the nano-branches, the number average molecular weight(Mn_(β)) of Block β may be controlled within the range of from 3K to100K, in another embodiment within the range of from 3K to 50K, and in afurther embodiment within the range of from 3K to 25K.

In preparing the nano-branches, the number average molecular weight(Mn_(α)) of Block α is approximately equal to the number averagemolecular weight (Mn_(γ)) of Block γ, i.e. Mn_(α)≈Mn_(γ). In a varietyof exemplary embodiments, Mn_(α) or Mn_(γ) may be controlled within therange of from 10K to 100K, in another embodiment within the range offrom 20K to 50K and in another embodiment within the range of from 20Kto 30K.

When copolymerizing multiple-vinyl-substituted aromatic hydrocarbonswith the vinyl aromatic hydrocarbon blocks of the tri-block andoptionally di-block copolymers in the micelle structures to form polymernano-branches, the weight concentration of the copolymers in the liquidhydrocarbon medium (M₁) may be broadly within the range of from 5 to40000, such as within the range of from 5 to 30000, or within the rangeof from 5 to 20000.

When di-block copolymers are prepared simultaneously with the tri-blockcopolymers, the ratio of di-functional initiator to mono-functionalinitiator can range from 100:0 to 1:100, in another embodiment from100:0 to 1:10, and in a further embodiment from 100:0 to 1:3.

(V) Disk-Like Nanoparticles

In another embodiment, the architecture of nanoparticles is controlledto be in the shape of a disk. In addition to the disk-like shape, whichfeatures a relatively constant thickness in each discrete nanoparticle,the disk-like nanoparticle architecture differs significantly from theabove tree-like dendrite, nano-rope, flower-like nanospheres, andnano-branch architectures in that the tri-block copolymer chains do notsubstantially bridge in the manner described above, e.g. less than 10%,such as less than 5%, or less than 1% of the tri-block copolymersbridge. In contrast, the tree-like dendrite, nano-rope, flower-likenanospheres, and nano-branch architectures are constructed by thebridging action of tri-block polymers between multiple micelle cores,which thereafter form a uniform elongated core.

A theoretical illustration of an example A-B-A disk-like nanoparticle isshown in FIG. 11 and a theoretical illustration of an example A-B-Cdisk-like nanoparticle is shown in FIG. 12. While not intending to bebound by theory, the illustrated structures are believed to be accuraterepresentation of disk-like nanoparticles, based on the TEM photographsin FIGS. 13-17 and other information. An imaginary axis 100 is shownrunning through the center of the disk-like nanoparticle. This axis 100is shown only for the purposes of illustration. Discrete lines are usedto illustrate the general shape and configuration of the core 105, shell110, radial surface 115, and axial surfaces 120, 122; however, theselines are not meant to imply that the disk-like nanoparticle is aperfect geometric cylinder with a perfectly spherical core.

The example disk-like nanoparticle has a core layer 105 that is centeredabout the axis 100. The core 105 comprises a cross-linked multi-vinylsubstituted aromatic hydrocarbon. The core 105 also comprises theportion of the tri-block copolymer that is crosslinked with it.

The example disk-like nanoparticle also has a shell layer 110, which hasa radial surface 115 at the outer radial edge and top and bottom axialsurfaces 120, 122. The radial surface 115 and top and bottom axialsurfaces 120, 122 are collectively outer surfaces. The shell layer 110is comprised of substantially uncrosslinked tri-block copolymer chains,each having a first block 125, a second block 130, and a third block135.

In FIG. 11, which depicts a disk-like nanoparticle with A-B-A tri-blockcopolymer chains, the first block 125 and third block 130 include vinylaromatic monomer units and are crosslinked with the core 105. A middleportion of the second block 130 includes conjugated diene monomer unitsa portion of which comprises the top and bottom axial surfaces 120, 122of the disk-like nanoparticle. As illustrated in FIG. 11, the tri-blockcopolymer chains are loop-like brushes or arms radiating out from thecore layer, wherein the first block begins the first end of the loop andthe second block begins the other end of the loop.

In FIG. 12, which depicts a disk-like nanoparticle with A-B-C tri-blockcopolymer chains, the first block 125 includes vinyl aromatic monomerunits and is crosslinked with the core 105. The second block 130radiates from the first block 125 and is bonded to the third block 135.The outer portion of the third block 135 comprises the top and bottomaxial surfaces 120, 122 of the disk-like nanoparticle. The second block130 includes conjugated diene monomer units, and the third blockincludes conjugated diene monomer units and/or vinyl aromatic monomerunits and/or vinyl-acrylate monomer units, and/or vinyl, N, orO-substituted aromatic monomer units. As illustrated in FIG. 11, thetri-block copolymer chains are hairy brushes or arms radiating out fromthe core layer.

In both example illustrations, the shell layer 110 is substantially notcross-linked. Substantially not crosslinked meaning that no more than20%, such as 0-10% or 0-3%, of the radiating tri-block polymer arms arecrosslinked. This feature provides improved interactive qualities withpolymeric matrices, such as rubber.

The disk-like nanoparticle forms via micelle assembly, as is describedabove. The second block radiates to the outside radial edge because itis more soluble in the selected hydrocarbon solvent than the first andthird blocks.

The radial diameter of the disk-like nanoparticle ranges from 10-10,000nm, such as 20-200 nm, or 25-90 nm and the axial thickness ranges from2-100 nm, such as 5-50 nm or 10-25 nm. The thickness is relativelyconstant across the entire radius, and is less than the radial diameter.The difference in thickness from the thickest to the thinnest area ofthe disk-like nanoparticle may be from 0 to 20%, such as from 0 to 10%,or from 0 to 5%.

The core of the disk-like nanoparticle is harder than the shell. Thatis, the core has a higher Tg than the shell. For example, the core mayhave a Tg of 50 to 200° C., such as 70 to 150° C., or 80 to 125° C.; andthe shell may have a Tg of less than 50° C. such as −150° C. to 40° C.,or −125° C. to 0° C.

In attempting to make the disk-like architecture it was unexpectedlydiscovered that two factors primarily controlled the formation of thenano-disk shape: (1) the use of a multi-functional lithiated aminecontaining initiator, as described below, for polymerizing the tri-blockcopolymer; and (2) controlling the weight ratio of the monomercomprising the first block and third block of the tri-block copolymerchains to the monomer comprising the second block is to be 100:1 to 1:1,such as from 20:1 to 2:1, 10:1 to 4:1, 9:1 to 2.3:1, or 7:1 to 2:1.

Regarding the multi-functional lithiated amine-containing initiator thatis used for polymerizing the tri-block polymer of the disk-likenanoparticles, the initiator comprises a multifunctional lithiated aminehaving at least two lithiated amines in one molecule of the initiator.For example, the initiator is a hydrocarbon solvent soluble, anionicpolymerization multi-lithio amine initiators that comprises at least twoor more lithio amines in one molecule and has the general formula:

where Q is (a) an element selected from the group consisting of O, S, N,P and Si or (b) an alkylene group having from 1 to 20 methylene groups,(e.g., methylene groups, O or S) and R₁ and R₂ and are selected from thegroup consisting of alkyls, cycloalkyls and aralkyls containing from 1to 20 carbon atoms (it being understood that alkyls, cycloalkyls andaralkyls are divalent in the context of R₁ and that the additional bondis created by the removal of a hydrogen from these moieties that areotherwise monovalent).

In one embodiment, 4,4′-trimethylenedipiperidine, a commerciallyavailable reagent from Aldrich was successfully metalated with n-BuLi(n-butyl lithium) and used for initiating the living polymerization ofdienes and/or aromatic vinyls in hexane solution without any polaradditives as shown in Scheme 1 below.

The advantages of this new difunctional initiator are: a) it is amono-modal living system such that the polymer formed has a mono-modalmolecular weight as characterized by gel permeation chromatography(GPC); b) an in-situ generation of the initiator; and c) the absence ofpolar additives. These advantages are especially useful for making headand tail di-functional polymers and SBS-tri-block copolymers with a lowT_(g) polybutadiene unit in the middle of the tri-block.

In another embodiment, a series of polyamines similar to4,4′-trimethylenedipiperidine (TMDP) can be used as di- or tri-N—Liinitiators for anionic polymerization of 1,3-butadiene and styrene.Examples of the di- and tri-lithio amine initiators include (scheme 2),but are not limited to, dilithio N,N′-diethyl-1,3-propanediamine(Li-DEPDA-Li), dilithio N,N′-diisopropyl-1,3-propanediamine(Li-DPPDA-Li), dilithio N,N′-diethyl-2-butene-1,4-diamine (Li-DEBDA-Li),trilithio tris[2-(methylamino)ethyl]amine (Tri-Li-TMAEA), trilithiotris[2-(isopropylamino)ethyl]amine (Tri-Li-TPAEA), andtrilithio-1,5,9-triazacyclododecane (Tri-Li-TACD).

The amount of initiator employed in the disk-like nanoparticle synthesiscan vary from 0.1 to 100 mmol of initiator per 100 g of monomer, such asfrom 0.33 to 10, or 0.2 to 1.0 mmol of lithium per 100 g of monomer.

The second factor that is believed to affect the formation of thedisk-like shape in the nanoparticle is the weight ratio of the monomercomprising the first block and third block of the tri-block copolymerchains to the monomer comprising the second block. For example, theweight of monomer in the first and third blocks of the monomer unitscompared to the weight of the monomer units in the second block may be100:1 to 1:1, such as from 50:1 to 1:1, 20:1 to 2:1, 10:1 to 4:1, 9:1 to2.3:1, or 7:1 to 2:1.

In the example disk-like nanoparticles, the tri-block copolymer chainsare either A-B-A copolymers, such as a vinyl aromatichydrocarbon—conjugated diene—vinyl aromatic hydrocarbon copolymer, orA-B-C copolymers. However, in other examples, a mixture of A-B-A andA-B-C copolymers may be employed. Furthermore, monoblock polymer mayalso be synthesized separately, added prior to cross-linking and therebybonded to the core. In addition diblock copolymers may be incorporatedas described supra.

In preparing the disk-like nanoparticles, the number average molecularweight (Mn₂) of the second block may be controlled within the range offrom 3K to 1000K, such as within the range of from 3K to 200K, or withinthe range of from 3K to 50K.

In example disk-like nanoparticles that have A-B-A tri-block copolymerchains in the shell, the number average molecular weight (Mn₁) of thefirst block is approximately equal to the number average molecularweight (Mn₃) of the third block, i.e. Mn₁≈Mn₃ (such as within 0-20% ofbeing the same Mn, for example, 0-10%, or 0-5%).

When copolymerizing multiple-vinyl-substituted aromatic hydrocarbonswith the vinyl aromatic hydrocarbon blocks of the tri-block copolymerchains, and optionally di-block copolymer chains in the micellestructures to form disk-like nanoparticles, the weight concentration ofthe copolymers in the liquid hydrocarbon medium (M₁) may be broadlywithin the range of from 0.01% to 20%, such as from 0.1% to 10%, or from0.1% to 2%.

When di-block copolymers are prepared simultaneously with the tri-blockcopolymers, the ratio of di-functional initiator to mono-functionalinitiator can range from 100:0 to 1:100, such as 100:0 to 1:10, and in afurther embodiment from 100:0 to 1:3. The same ratios can be used whenmonoblock polymer is added.

The disk-like nanoparticle is made by copolymerizing two or more monomerspecies with a multi-functional lithiated amine containing initiator, toform the second block to form tri-block copolymers, and thencross-linking to form a core. The multi-functional lithiatedamine-containing initiator may be selected from the species describedabove.

To make the tri-block copolymers, the second block is polymerized firstwith the multi-functional lithiated initiator. The first and thirdblocks are then copolymerized with the second block to obtain thetri-block copolymer chains.

The first and third blocks comprise vinyl aromatic monomers. The vinylaromatic monomer may be selected from the species disclosed above.Different monomer species may be selected if an A-B-C tri-blockcopolymer is desired. For example, the monomers for the third block mayinclude conjugated diene monomer units and/or vinyl aromatic monomerunits and/or vinyl-acrylate monomer units, and/or vinyl, N, orO-substituted aromatic monomer units.

The second block comprises a conjugated diene monomer. The conjugateddiene monomer may be selected from the species disclosed above.

The polymerization is performed in a liquid hydrocarbon medium andmicelle structures are formed therein. The second block should beselected to be more soluble in the hydrocarbon solvent than the firstand third blocks, so that the second block will be on the outer surfaceof the micelle and the first and third blocks will be directed towardsthe center of the micelle. The hydrocarbon solvent may be selected fromthose disclosed above.

After copolymerization of the tri-block copolymers and assembly intomicelle structures, in the case of A-B-A tri-block copolymer chains,multiple-vinyl-substituted aromatic hydrocarbons cross-link the firstand third blocks of the tri-block copolymers in the micelle structuresto form a cross-linked core. In the case of A-B-C tri-block copolymerchains only the first block may be crosslinked with the core. Thiscross-linked core stabilizes and holds the micelles together.

The multiple-vinyl-substituted monomer may be selected from the speciesdisclosed above.

The disk-like nanoparticles can be included in rubber compositions asdiscussed below in detail. The shape of the disk-like nanoparticles isexpected to provide an increase in viscosity and improved gaspermeability in rubber compositions. This makes it an excellentpotential additive for a tire rubber composition.

The non-spherical polymer nanoparticles may be widely utilized in thetechnical fields of rubbers, plastics, tire manufacture, medicine,catalysis, combinatorial chemistry, protein supports, magnets,photonics, electronics, cosmetics, and all other applications envisionedby the skilled artisan. For example, they can be used as processing aidsand reinforcing fillers in rubber compounds.

In a variety of exemplary embodiments, rubber articles such as tires maybe manufactured from a formulation comprising the polymer nanoparticlesas described supra. References for this purpose may be made to, forexample, U.S. Pat. No. 6,875,818.

In one embodiment, a rubber composition comprises (a) a rubber matrix;and (b) the non-spherical polymeric nanoparticles as described above.The typical amount of the polymeric nanoparticles in the rubbercomposition may broadly range from 1 phr to 150 phr, in anotherembodiment from 1 phr to 50 phr, in another embodiment from 1 phr to 20phr, based on 100 parts per hundred parts rubber in the composition.

The terms “rubber” and “elastomer” if used herein, may be usedinterchangeably, unless otherwise prescribed. The terms such as “rubbercomposition”, “compounded rubber” and “rubber compound”, if used herein,are used interchangeably to refer to “rubber which has been blended ormixed with various ingredients and materials” and “rubber compounding”or “compounding” may be used to refer to the “mixing of such materials”.Such terms are well known to those having skill in the rubber mixing orrubber compounding art.

The rubber matrix may comprise any solution polymerizable or emulsionpolymerizable elastomer, for example, diene homopolymers, and copolymersand terpolymers of conjugated diene monomers with vinyl aromaticmonomers and trienes such as myrcene. Exemplary diene homopolymers arethose prepared from diolefin monomers having from 4 to 12 carbon atoms.Exemplary vinyl aromatic polymers are those prepared from monomershaving from 8 to 20 carbon atoms. Examples of such monomers may bereferred to the monomers for the nanoparticle formation as describedsupra. In one embodiment, the conjugated diene monomer and vinylaromatic monomer are used at the weight ratios of from 1:99 to 99:1, inanother embodiment the weight ratios are from 2:98 to 98:2. Thecopolymers are, for example, random copolymers which result fromsimultaneous copolymerization of the monomers with randomizing agents,as is known in the art.

The rubber matrix may comprise any conventionally employed treadstockrubber such as natural rubber, synthetic rubber and blends thereof. Suchrubbers are well known to those skilled in the art and include syntheticpolyisoprene rubber, styrene-butadiene rubber (SBR),styrene-isoprene-butadiene rubber, styrene-isoprene rubber,butadiene-isoprene rubber, polybutadiene, butyl rubber, neoprene,ethylene-propylene rubber, ethylene-propylene-diene rubber (EPDM),acrylonitrile-butadiene rubber (NBR), silicone rubber, thefluoroelastomers, ethylene acrylic rubber, ethylene vinyl acetatecopolymer (EVA), epichlorohydrin rubbers, chlorinated polyethylenerubbers, chlorosulfonated polyethylene rubbers, hydrogenated nitrilerubber, tetrafluoroethylene-propylene rubber, and the like, and themixture thereof.

Rubber matrix used in tires, hoses, power transmission belts and otherindustrial products has good compatibility with fillers, such as carbonblack and silica. To attain improved interaction with fillers, therubber matrix can be functionalized with various compounds, such asamines.

In one embodiment, carbon black can be used as a reinforcing filler inthe rubber compounds of the present invention. The carbon black may beselected from any of the commonly available carbon blacks, but thosehaving a surface area (EMSA) of at least 20 m²/g, such as at least 35m²/g, or up to 200 m²/g or higher. Surface area values may be determinedby ASTM D-1765 using the cetyltrimethyl-ammonium bromide (CTAB)technique. Among the useful carbon blacks are furnace black, channelblacks and lamp blacks. More specifically, examples of useful carbonblacks include super abrasion furnace (SAF) blacks, high abrasionfurnace (HAF) blacks, fast extrusion furnace (FEF) blacks, fine furnace(FF) blacks, intermediate super abrasion furnace (ISAF) blacks,semi-reinforcing furnace (SRF) blacks, medium processing channel blacks,hard processing channel blacks and conducting channel blacks. Othercarbon blacks which can be utilized include acetylene blacks. A mixtureof two or more of the above blacks may also be used. Exemplary carbonblacks include N-110, N-220, N-339, N-330, N-343, N-351, N-550, N-660,and the like, as designated by ASTM D-1765-82a. The carbon blacksutilized may be in pelletized form or an unpelletized flocculent mass.For more uniform mixing, unpelletized carbon black is used.

In certain embodiments, the amount of carbon black may broadly rangefrom 10 phr to 150 phr, from 20 phr to 120 phr, and from 30 phr to 100phr.

Silica may also be used as a filler in the rubber compounds describedherein. Exemplary silica fillers include, but are not limited to,precipitated amorphous silica, wet silica (hydrated silicic acid), drysilica (anhydrous silicic acid), fumed silica, and precipitatedamorphous wet-process, hydrated silicas. In one embodiment, the surfacearea of the silica filler is from 32 m²/g to 400 m²/g, in anotherembodiment the surface area is from 100 m²/g to 250 m²/g, and in anotherembodiment the surface area is from 150 m²/g to 220 m²/g. The pH of thesilica filler is generally within the range of 5.5 to 7, and in anotherembodiment within the range of 5.5 to 6.8.

The silica filler may be selected from any of the commonly availablesilicas. Some of the commercially available silicas which can be usedinclude, but are not limited to, Hi-Sil® 190, Hi-Sil® 210, Hi-Sil® 215,Hi-Sil® 233, Hi-Sil® 243, and the like, produced by PPG Industries(Pittsburgh, Pa.). A number of useful commercial grades of differentsilicas are also available from Degussa Corporation (e.g., VN2, VN3),Rhone Poulenc (e.g., Zeosil® 1165 MP), and J.M. Huber Corporation.

To improve filler dispersion and reduce agglomeration andre-agglomeration of silica aggregates, a coupling agent may be usedalong with silica fillers. Typically, a silica coupling agent has atleast two functional groups, one of which is reactive with the silicasurface such as a silyl group, and another one can bind to the rubberymatrix such as mercapto, amino, vinyl, epoxy or sulfur group. Exemplarycoupling agents include, but are not limited to, mercaptosilanes andorganosilane polysulfides.

A silica dispersing aid such as monofunctional silica shielding agentmay be used along with silica fillers. Examples of silica dispersingaids include silica hydrophobating agents that chemically react with thesurface silanol groups on the silica particles but are not reactive withthe matrix elastomer, and agents which physically shield the silanolgroups to prevent reagglomeration (flocculation) of the silica particlesafter compounding. Specific examples of silica dispersing aid includealkyl alkoxysilanes, glycols (e.g., diethylene glycol or polyethyleneglycol), fatty acid esters of hydrogenated and non-hydrogenated C₅ andC₆ sugars (e.g., sorbitan oleates, and the like), polyoxyethylenederivatives of the fatty acid esters, among others.

If used, silica may be present in the rubber compounds in an amount offrom 10 phr to 150 phr, in another embodiment from 20 phr to 120 phr,and in a further embodiment from 30 phr to 100 phr.

In certain embodiments, a combination of silica and carbon black areutilized as reinforcing fillers in rubber compounds intended for use invarious rubber products, including treads for tires.

Other fillers can also be utilized as processing aids which include, butare not limited to, mineral fillers, such as aluminum silicate, calciumsilicate, magnesium silicate, clay (hydrous aluminum silicate), talc(hydrous magnesium silicate), and mica as well as non-mineral fillerssuch as urea and sodium sulfate.

Oil can be included in the rubber compounds as a processing aid.Examples of suitable oils include aromatic, naphthenic, paraffinicprocessing oils, as well as combinations of the same. In one embodiment,the amount of oil may range from 0 phr to 150 phr, in another embodimentfrom 10 phr to 120 phr, and in yet another embodiment from 15 phr to 70phr.

A vulcanizing agent is used to cure the rubber compounds describedherein. For a general disclosure of suitable vulcanizing agents, one canrefer to Kirk-Othmer, Encyclopedia of Chemical Technology, 3^(rd) ed.,Wiley Interscience, N.Y. 1982, Vol. 20, pp. 365 to 468, particularly“Vulcanization Agents and Auxiliary Materials,” pp. 390 to 402.Vulcanizing agents can be used alone or in combination. In someembodiments, sulfur or peroxide-based vulcanizing agent may be employed.Examples of suitable sulfur vulcanizing agents include “rubber maker's”soluble sulfur; elemental sulfur (free sulfur); sulfur donatingvulcanizing agents such as organosilane polysulfides, amine disulfides,polymeric polysulfides or sulfur olefin adducts; and insoluble polymericsulfur. In one embodiment, the sulfur vulcanizing agent is solublesulfur or a mixture of soluble and insoluble polymeric sulfur.

The amount of vulcanizing agent, may range from 0.1 phr to 10 phr, inanother embodiment from 1 phr to 5 phr, and in another embodiment from 1phr to 3 phr.

A vulcanization accelerator may be used along with a vulcanizing agent.The vulcanization accelerators are not particularly limited. Examples ofvulcanization accelerators include thiazol vulcanization accelerators,such as 2-mercaptobenzothiazol, dibenzothiazyl disulfide,N-cyclohexyl-2-benzothiazyl-sulfenamide (CBS),N-tert-butyl-2-benzothiazyl sulfenamide (TBBS), and the like; guanidinevulcanization accelerators, such as diphenylguanidine (DPG) and thelike; amines; disulfides; thiurams; sulfenamides; dithiocarbamates;xanthates; and thioureas; among others.

The amount of vulcanization accelerator, if used, may range from 0.1 phrto 10 phr, in another embodiment from 0.1 phr to 5 phr, and in anotherembodiment 0.1 phr to 3 phr.

The composition may be compounded by methods generally known in therubber compounding art, such as mixing the rubbery matrix polymer andthe non-spherical nanoparticles with conventional amounts of commonlyused additive materials such as, in addition to those identified above,for example, activators, retarders, other processing additives such asresins, and including tackifying resins, plasticizers, pigments, fattyacids, zinc oxide, waxes, antioxidants, anti-ozonants, and peptizingagents, using standard rubber mixing equipment and procedures.

A vulcanized rubber product may be produced by thermomechanically mixingrubbery matrix polymer, the nanoparticles, and various ingredients in asequentially step-wise manner in a mixer, followed by shaping and curingthe composition.

The composition described herein can be used for various purposes. Forexample, it can be used for various rubber compounds, such as a tiretreadstock, sidewall stock or other tire component stock compounds. Suchtires can be built, shaped, molded and cured by various methods whichare known and will be readily apparent to those having skill in suchart. In one embodiment, a molded unvulcanized tire is placed into avulcanizing mold and then vulcanized to produce a tire.

The following examples are included to provide additional guidance tothose skilled in the art in practicing the claimed invention. Theexamples provided are merely representative of the work that contributesto the teaching of the present application. Accordingly, these examplesare not intended to limit the invention, as defined in the appendedclaims, in any manner.

EXAMPLES

In Examples 1-3, a 2-gallon reactor equipped with external heatingjacket and internal agitation was used for all materials preparation.Styrene in hexane (33 weight percent styrene), hexane, butyllithium(1.54 M) and BHT were used as supplied. Isoprene (100% pure) was storedon aluminum oxide beads and calcium hydride under nitrogen. Technicalgrade divinyl benzene (80%, mixture of isomers, purchased from Aldrich,item 41,456-5) was stored on aluminum oxide beads and calcium hydrideunder nitrogen.

The di-lithium solution (˜0.5M) was made according to the followingprocedure. To a clean, dry, N₂ purged closed bottle is charged equimolaramounts of triethyl amine and butyllithium. Then 1,3-diisopropenylbenzene is added at a target molar ratio of 1.2 to the sec-butyllithium.The bottle is then heated with agitation for 2.0 hours at 50° C.

For the following examples, sec-BuLi (57.14 ml, 1.4 M in cyclohexane,purchased from Aldrich) was added to a solution of1,3-diisopropenylbenzene (6.84 ml, 40 mmol) and triethylamine (11.15 ml,80 mmol) via a syringe at room temperature. The solution was agitatedand heated at 50° C. for 2 hours. The deep red Li diadduct (abbreviatedas DiLi, 0.53 M) was used as the di-lithium initiator and stored infreezer until use.

Example 1

The reactor was charged with 4 lbs. hexane and 0.373 lbs. isoprene (IP).The jacket of the reactor was heated to 135° F. When the batch reached135° F., 15 ml of 0.5 M di-lithium solution was added. After 2 hours,1.5 lb. styrene/hexane blend (containing 33 wt % styrene) was added tothe reactor which was maintained at 135° F. An exothermic peak wasobserved after 20 minutes. After 2 hours, 50 ml divinyl-benzene (DVB)was charged into the solution. The solution was allowed to react for anadditional 2 hours, and then the reaction mixture was dropped into anisopropanol/acetone solution containing BHT (about 500 mL/2 L). Thesolid was then filtered through a cheese-cloth and dried in vacuum. Theproduct could be dissolved in a number of solvents, such as THF,toluene, and hexane. Those solutions were usually thick and gel-like,indicating that the synthesized polymer might have supra-architectures.

GPC analysis of the intermediate product, based on a polystyrene/THFstandard, indicates block copolymer having a number average molecularweight (Mn) of 121K and a polydispersity (Mw/Mn) of 1.17. The blockcopolymer was designed as a tri-block, in which the polystyrene blockhad a target Mn of 35K and the isoprene blocks had a target Mn of 25K.The TEM analysis was taken on a hexane solution of the final product at10⁻⁵ wt % concentration. A drop of the diluted solution was coated on acarbon coated copper micro-grid. After the solvent was vaporized, thegrid was stained with RuO₄ and was then examined by TEM (see FIG. 1). Itwas found that the product synthesized contained tree-like dendritescomposed of linked nano-spherical particles.

Example 2

In Example 2, the size of the isoprene block of the tri-block polymerswas decreased from a target Mn of 25K to 14K. The reactor was chargedwith 4 lbs. hexane and 0.229 lbs. isoprene. The jacket of the reactorwas heated to 135° F. When the batch reached 135° F., 15 ml of 0.5 Mdi-lithium solution was added. After 2 hours, 1.5 lbs. styrene/Hexaneblend (containing 33 wt % styrene) was added to the reactor which wasmaintained at 135° F. An exothermic peak was observed after 20 minutes.After 1.5 hours, the color of the solution was yellow. 50 ml divnylbenzene (DVB) was then charged into the solution. After about 7 minutes,the agitation was stopped. The solution was allowed to react for anadditional 1.5 hours; the reaction mixture was then dropped into anisopropanol/acetone solution containing BHT (about 500 mL/2 L). Thesolid was then filtered through a cheese-cloth and dried in vacuum.

GPC analysis of the intermediate product, based on a polystyrene/THFstandard, indicated block copolymer having a number average molecularweight (Mn) of 79, and a polydispersity (Mw/Mn) of 1.2. A TEM analysisof a hexane solution of the final product at 10⁻⁵ wt % concentration wasconducted. A drop of the diluted solution was coated on a carbon coatedcopper micro-grid. After the solvent was vaporized, the grid was stainedwith RuO₄, and was then examined by TEM (see FIG. 2). The results showedthat the product synthesized contained nano-rope structures.

Example 3

In Example 3, the size of the isoprene block of the tri-block polymerswas further decreased from a target Mn of 14K to 9K, and thenano-assembly of polymer chains changed to spherical particles withflower-like inner structures. The reactor was charged with 2 lbs. hexaneand 0.195 lbs. isoprene. The jacket of the reactor was heated to 135° F.When the batch reached 135° F., 15 ml of 0.5 M di-lithium solution wereadded. After 2 hours, 1.5 lb. styrene/Hexane blend (containing 33 wt %styrene) were added to the reactor which was maintained at 135° F. Anexothermic peak was observed after 20 minutes. After 2 hours, the colorof solution was orange. 50 ml divnyl benzene (DVB) was then charged intothe solution. The solution was allowed to react for an additional 2.5hours. The reaction mixture was then dropped in an isopropanol/acetonesolution containing BHT (about 500 mL/2 L). The solid was then filteredthrough cheesecloth and dried in vacuum.

GPC analysis of the intermediate product, based on a polystyrene/THFstandard, indicated block copolymer having a number average molecularweight (Mn) of 58K and a polydispersity (MW/Mn) of 1.03. The TEManalysis was taken on a hexane solution of the final product at 10⁻⁵ wt% concentration. A drop of the diluted solution was coated on a carboncoated copper micro-grid. After the solvent was vaporized, the grid wasstained with RuO₄ and was then examined by TEM (see FIG. 3). The resultsshowed that the product synthesized contained spherical particles withflower-like inner structures.

In Examples 4-7, a 2-gallon reactor equipped with external jackedheating and internal agitation was used for all material preparation.Styrene in hexane (33 weight percent styrene), hexane, butyllithium(BuLi, 1.6 M) and BHT were used as supplied. Isoprene (100% pure) wasstored on aluminum oxide beads and calcium hydride under nitrogen.Technical grade divinylbenzene (80%, mixture of isomers, purchased fromAldrich, item 41,456-5) was stored on aluminum oxide beads and calciumhydride under nitrogen. The di-lithium solution (˜0.5M) was madeaccording to the method described above.

Example 4

The reactor was charged with 4 lbs. hexane and 0.231 lbs. isoprene. Thejacket of the reactor was heated to 135° F. When the batch reached 135°F., 7.5 ml of 0.5 M di-lithium solution and 2.4 ml of 1.6 M BuLi wereadded. After 2 hours, 1.5 lbs. styrene/hexane blend (containing 33 wt %styrene) was added to the reactor that was maintained at 135° F. Anexothermic peak was observed after 20 minutes. After 1.5 hours, 50 mldivinyl benzene (DVB) was charged into the solution. The solution wasallowed to react for an additional 1.5 hours, and then the reactionmixture was dropped in an isopropanol/acetone solution containing BHT(about 500 mL/2 L). The solid was then filtered through a cheese clothand dried in vacuum.

A drop of the diluted solution was coated on a carbon coated coppermicro-grid. After the solvent was vaporized, the grid was stained withRuO₄ and was then examined by TEM. As shown in FIG. 5, the productsynthesized contained spheres, chains, dumbbells and other highlyorganized structures.

Example 5

In Example 5, the size of the isoprene block of the tri-block polymerswas increased over that of Example 4. The reactor was initially chargedwith 4 lbs. hexane and 0.31 lbs. isoprene. The synthesis process and thecharge of other components was the same as that described in Example 4.

A TEM analysis was performed on a hexane solution of the final productat 10⁻⁵ wt % concentration. A drop of the diluted solution was coated ona carbon coated copper micro-grid. After the solvent was vaporized, thegrid was stained with RuO₄ and was then examined by TEM. As shown inFIG. 6, the product synthesized contained short nano-ropes.

Example 6

In Example 6, the size of the isoprene block of the tri-block polymerwas reduced, resulting in the formation of nano branches. The reactorwas charged with 4 lbs. hexane and 0.185 lbs. isoprene. The jacket ofthe reactor was heated to 135° F. When the batch reached 135° F., 7.5 mlof 0.5 M dilithium solution and 2.4 ml of 1.6 M BuLi were added. After 2hours, 1.5 lbs. styrene/Hexane blend (containing 33 wt % styrene) wasadded to the reactor that was maintained at 135° F. An exothermic peakwas observed after 20 minutes. After 1.5 hours, the color of solutionwas orange. 50 ml divinyl-benzene (DVB) was then charged into thesolution. The solution was allowed to react for an additional 1.5 hours;and the reaction mixture was then dropped in an isopropanol/acetonesolution containing BHT (about 500 mL/2 L). The solid was then filteredthrough a cheese cloth and dried in vacuum.

A TEM analysis was conducted on a hexane solution of the final productat 10⁻⁵ wt % concentration. A drop of the diluted solution was coated ona carbon coated copper micro-grid. After the solvent was vaporized, thegrid was stained with RuO₄ and was then examined by TEM. As shown inFIG. 7, the product contained short nano-sized branches. One of thebranches looked somewhat rigid (see FIG. 8) and appeared to stretch outin three dimensions.

Example 7

By adjusting types and amounts of materials added to the reactor, aproduct with an architecture of narrowly distributed nano-branches wasformed. The reactor was charged with 4 lbs. hexane and 1.15 lbs.Butadiene/Hexane solution (21.4% Butadiene). The jacket of the reactorwas heated to 135° F. When the batch reached 135° F., 10 ml of 0.5 Mdilithium solution and 1 ml of 1.6 M BuLi were added. After 2 hours, 1.5lbs. styrene/Hexane blend (containing 33 wt % styrene) were added to thereactor that was maintained at 135° F. An exothermic peak was observedafter 20 minutes. After 1.5 hours, 50 ml divinyl-benzene (DVB) was thencharged into the solution. The solution was allowed to react for anadditional 1.5 hours; and the reaction mixture was then dropped in anisopropanol/acetone solution containing BHT (about 500 mL/2 L). Thesolid was then filtered through a cheese cloth and dried in vacuum.

A TEM analysis was conducted on a hexane solution of the final productat 10⁻⁵ wt % concentration. A drop of the diluted solution was coated ona carbon coated copper micro-grid. After the solvent was vaporized, thegrid was stained with RuO₄ and was then examined by TEM. As shown inFIGS. 9 and 10, the product contained narrowly distributed nano-sizedbranches.

Examples 8, 9 and 10 Application of the Nano-Branches in a RubberFormulation

Three rubber compositions were prepared according to the formulationshown in Tables 1 and 2 by selectively using the nanoparticles ofExamples 6 and 7 to replace 10 phr of SBR in the compound formulation(i.e., Examples 9 and 10).

In each sample, the ingredients were mixed according to the method ofTable 3. The final stocks were sheeted and cured at 165° C. for 15minutes.

TABLE 1 Composition for Master Batch (in phr) Ex. 8 Ex. 9 Ex. 10 SBR100.00 90.00 90.00 Example 6 (nanoparticle) 0 10.00 0 Example 7(nanoparticle) 0 0 10.00 Carbon Black (N343) 50.00 50.00 50.00 AromaticOil 15.00 15.00 15.00 Zinc Oxide 3.00 3.00 3.00 Hydrocarbon Resin(tackifiers) 2.00 3.00 3.00 Antioxidant 0.95 0.95 0.95 Stearic Acid 2.002.00 2.00 Wax 1.00 1.00 1.00

TABLE 2 Composition for Final Batch (in phr) Sulphur ~1.30 ~1.30 ~1.30Cyclohexyl-benzothiazole Sulfonamide (accelerator) 1.40 1.40 1.40Diphenylguanidine (accelerator) 0.20 0.20 0.20

TABLE 3 Mixing Conditions. Mixer: 300 g Brabender  Agitation Speed: 60rpm Mater Batch Stage Initial Temperature 110° C.   0 min chargingpolymers 0.5 min charging oil and Carbon Black 5.0 min drop Final BatchStage Initial Temperature 75° C.   0 sec charging master stock  30 seccharging curing agent and accelerators  75 sec drop

The analysis of the vulcanized rubber compounds of Examples 8-10,included tensile strength, tear strength, hysteresis loss gave theresults, as shown in Table 4. Measurement of tensile strength was basedon conditions of ASTM-D 412 at 22° C. Test specimen geometry was takenthe form of a ring of a width of 0.05 inches and of a thickness of 0.075inches. The specimen was tested at a specific gauge length of 1.0 inch.The measurement of tear strength was based on conditions of ASTM-D 624at 170° C. Test specimen geometry was taken the form of a nicked ring(ASTM-624-C). The specimen was tested at the specific gauge length of1.750 inches. The hysteresis loss was measured with a DynastatViscoelastic Analyzer. Test specimen geometry was taken the form of acylinder of a length of 15 mm and of a diameter of 10 mm. The followingtesting conditions were employed: frequency 1 Hz, 2 kg static load and1.25 kg dynamic load.

TABLE 4 Ex. 8 Ex. 9 Ex. 10 130° C. ML4 36.38 39 41.8 MDR 2000 165° C. MH13.17 13.22 13.61 T90 5.6 5.94 5.76 Shore A 22c (3 sec) 55.4 64.3 62.2100° C. (3 sec) 53.5 57.4 56.4 Ring Tensile at 23° C. Tb(MPa) 16.7316.44 18.85 Eb (%) 548.4 502.9 523.2 M300 7.07 8.6 9.25 M50 0.93 1.251.25 Ring Tensile at 100° C. Tb (MPa) 8.36 8.5 8.54 Eb (%) 377.8 366.6352 M300 5.94 6.42 6.81 M50 0.69 0.8 0.78 Tear Strength (kN/m) 16.7 17.118.0 Ring Tear travel (%) 170° C. 410 410 395 Tg of Compound (from tandelta) −42 −42 −42 Stanley London (concrete) 56.2 57 52.6 Dynstat tandelta at 50° C. 0.1906 0.2351 0.2195 K′ (lbf/in) 141.14 241.16 203.38Tan delta 25° C. 0.2311 0.2600 0.2539 K′ (lbf/in) 178.13 385.19 277.32Tan delta 0° C. 0.2571 0.2528 0.2567 K′ (lbf/in) 259.02 639.71 494.91Tan delta −20° C. 0.2967 0.2838 0.3269 K′ (lbf/in) 374.23 890.85 689.54

Examples 11-13 Disk-Like Nanoparticles Dilithium Initiator Preparation

Two methods were used to synthesize the dilithium initiator. In method1, 4,4′-trimethylenedipiperidine, from Aldrich, was first metalated witha mole equivalent amount of n-butyl lithium. The resultant material wasthen used to initiate the polymerization of dienes.

In method 2, 4,4′-trimethylenedipiperidine, from Aldrich, was firstcharged into a diene monomer solution. This solution was then chargedwith a mole equivalent amount of n-butyl lithium.

Method 2 was relatively better in industrial production in terms offeasibility and reliability. Although the resultant material easilyphases out from hydrocarbon solution, after initializing the butadienepolymerization, it stays in solution.

Synthesis of Disk-Like Nanoparticles Example 11

To a two-gallon, N₂-purged reactor equipped with a stirrer was added4.99 lb hexane, and 0.92 lb butadiene/hexane blend (containing 21.7 wt %of butadiene). The reactor was then set to 135° F. After the temperaturewas stabilized, 4 ml (1 M) of 4,4′-trimethylenedipiperidine in tolueneand 5.4 ml (1.6 M) of butyllithium in hexane were charged to thereactor. After three hours, 2.7 ml of OOPs (1.6 M) in hexane was chargedto the reactor. Following that immediately, the reactor was charged with2.42 lb styrene/Hexane blend (containing 33 wt % styrene). The reactionwas continued for another 3 hrs. Then the reactor was charged with 50 mlof divinyl benzene. After 2.5 more hours, the reaction was stopped bydropping the product into isopropenol and then treated with ˜1% Irganox1520L antioxidant (AO) (4,6-bis(octylthiomethyl)-o-cresol). The productcomposed 20 wt % butadiene and 80 wt % styrene.

A TEM analysis was done on a hexane solution of the final product at10⁻⁵ wt % concentration. A drop of the diluted solution was coated on acarbon coated copper micro-grid. After the solvent was vaporized, thegrid was stained with OsO₄ and was then examined by TEM. The result isshown in FIG. 13.

The same TEM analysis was also done on a toluene solution of the finalproduct at 10⁻⁵ wt % concentration. The result is shown in FIG. 14.

Both TEM results showed that the synthesized product contains disk-likenanoparticles. The disks display uniform gray color, which indicatesthat within the disk the thickness is mostly constant. Overlappingbetween two disks is shown as an oval-shaped dark color. This isillustrated in FIG. 18 showing a collection of nanoparticles and anillustration how they are overlapping. The thickness of the disk canalso be measured in the TEM using shadow-casting technique. The diskshave a thickness around 5 to 10 nm.

Example 12

The same procedure as that shown in Example 11 was used, except for theamounts of materials used. In this example, the reactor was firstcharged with 5.15 lb of hexane, and 0.46 lb of butadiene/hexane blend(containing 21.7 wt % of butadiene). The reactor was then set to 135° F.After the temperature was stabilized, 4 ml (1 M) of4,4′-trimethylenedipiperidine in toluene and 5.4 ml (1.6 M) ofbutyllithium in hexane were charged to the reactor. After three hours,2.7 ml of OOPs (1.6M) in hexane was charged to the reactor. Then, thereactor was charged with 2.73 lb of styrene/hexane blend (containing 33wt % styrene). The reaction continued for another 3 hrs. Subsequently,the reactor was charged with 50 ml of divinyl benzene. After 2.5 morehours, the reaction was stopped by dropping the product into isopropenoland then treated with AO (˜1% Irganox-1520L). The product was 10 wt %butadiene and 90 wt % styrene.

A drop of the diluted hexane solution, ˜1×10⁻⁵ wt %, was coated on acarbon coated copper microgrid. After the solvent was vaporized, thegrid was stained with 0s0₄ and was then examined by TEM. The result isshown in FIG. 15 and FIG. 16.

Example 13

Once again, the same procedure as that shown in Example 11 was used,except for the amounts of materials used. In this example, the reactorwas first charged with 4.83 lb of hexane, and 1.38 lb ofbutadiene/Hexane blend (containing 21.7 wt % of butadiene). The reactorwas then set to 135° F. After the temperature was stabilized, 4 ml (1 M)of 4,4′-trimethylenedipiperidine in toluene and 5.4 ml (1.6 M) ofbutyllithium in hexane were charged to the reactor. After three hours,2.7 ml of OOPs (1.6 M) in hexane was charged to the reactor. Then, thereactor was charged with 2.12 lb styrene/hexane blend (containing 33 wt% styrene). The reaction was continued for another 3 hrs. Then thereactor was charged with 50 ml of divinyl benzene. After 2.5 more hours,the reaction was stopped by dropping the product into isopropenol andthen treated with AO (˜1% Irganox-1520L). The product was 30 wt %butadiene and 70 wt % styrene.

A drop of the diluted hexane solution, ˜1×10⁻⁵ wt %, was coated on acarbon coated copper microgrid. After the solvent was vaporized, thegrid was stained with OsO₄ and was then examined by TEM. The result isshown in FIG. 17. The particles were not well-organized in term ofshapes.

This written description sets forth the best mode of the invention, anddescribes the invention so as to enable a person skilled in the art tomake and use the invention, by presenting examples. The patentable scopeof the invention is defined by the claims, and may include otherexamples that occur to those skilled in the art.

It is claimed:
 1. A method for making disk-like nanoparticles in aliquid hydrocarbon medium, the nanoparticles having a core layer and ashell layer, the shell layer comprising tri-block copolymer chainshaving a first block, a second block, and a third block, the methodcomprising the steps of: polymerizing a conjugated diene monomer with amulti-functional initiator; copolymerizing a vinyl aromatic monomer toform the first and third blocks, thereby producing the tri-blockcopolymer chains; assembling the tri-block copolymer chains in theliquid hydrocarbon medium to form micelle structures; and crosslinking amultiple-vinyl-substituted aromatic hydrocarbon with the tri-blockcopolymer chains in the micelle structures to form a cross-linked coreand to form polymer nanoparticles.
 2. The method of claim 1, wherein theinitiator is a hydrocarbon solvent soluble, anionic polymerizationmulti-lithio amine initiator that comprises at least two or more lithioamines in one molecule and has the general formula:

wherein Q is (a) an element selected from the group consisting of O, S,N, P and Si or (b) an alkylene group having from 1 to 20 methylenegroups, and R₁ and R₂ are selected from the group consisting of alkyls,cycloalkyls and aralkyls containing from 1 to 20 carbon atoms.
 3. Themethod of claim 1, wherein the initiator is dilithioN,N′-diethyl-1,3-propanediamine (Li-DEPDA-Li), dilithioN,N′-diisopropyl-1,3-propanediamine (Li-DPPDA-Li), dilithioN,N′-diethyl-2-butene-1,4-diamine (Li-DEBDA-Li), trilithiotris[2-(methylamino)ethyl]amine (Tri-Li-TMAEA), trilithiotris[2-(isopropylamino)ethyl]amine (Tri-Li-TP AEA), ortrilithio-1,5,9-triazacyclododecane (Tri-Li-T ACD).
 4. The method ofclaim 1, wherein the weight ratio of the monomer units comprising thefirst block and third block to the monomer units comprising the secondblock is 50:1 to 1:1.
 5. The method of claim 1, further comprising thestep of adding a monoblock polymer and/or copolymerizing a diblockcopolymer, and cross-linking the mono block polymer and/or diblockcopolymer with the core.
 6. The method of claim 1, wherein the tri-blockcopolymer chains are A-B-A copolymer chains.
 7. The method of claim 1further comprising the step of adding a monoblock polymer and/or addingor synthesizing a diblock copolymer prior to the crosslinking step.
 8. Amethod for making a composition comprising: mixing disk-likenanoparticles with a rubber matrix; the disk-like nanoparticles having acore layer comprising a cross-linked multi-vinyl substituted aromatichydrocarbon; a shell layer comprising tri-block copolymer chains, eachhaving a first, a second, and a third block; the first and third blockscomprising a vinyl aromatic monomer and being crosslinked with the core;the second block comprising a conjugated diene monomer and comprisingtop and bottom surfaces of the disk-like nanoparticles; the weight ratioof the monomers comprising the first block and third block to themonomers comprising the second block is 100:1 to 1:1.
 9. The method ofclaim 8, wherein the weight ratio of the monomer units comprising thefirst block and third block to the monomer units comprising the secondblock is 50:1 to 1:1.
 10. The method of claim 8, wherein the disk-likenanoparticles are initiated with dilithioN,N′-diethyl-1,3-propanediamine (Li-DEPDA-Li), dilithioN,N′-diisopropyl-1,3-propanediamine (Li-DPPDA-Li), dilithioN,N′-diethyl-2-butene-1,4-diamine (Li-DEBDA-Li), trilithiotris[2-(methylamino)ethyl]amine (Tri-Li-TMAEA), trilithiotris[2-(isopropylamino)ethyl]amine (Tri-Li-TP AEA), ortrilithio-1,5,9-triazacyclododecane (Tri-Li-T ACD).
 11. The method ofclaim 8, wherein the disk-like nanoparticles are initiated withLi-4,4′trimethylenedipiperidine-Li.
 12. The method of claim 8, whereinthe tri-block copolymer chains are A-B-A copolymer chains.
 13. Themethod of claim 8, further comprising vulcanizing the composition. 14.The method of claim 8, further comprising mixing a reinforcing fillerselected from carbon black, silica, or both.
 15. The method of claim 8,further comprising mixing a filler selected from the group consistingof: aluminum silicate, calcium silicate, magnesium silicate, clay(hydrous aluminum silicate), talc (hydrous magnesium silicate), andmica, urea, sodium sulfate, and mixtures thereof.
 16. The method ofclaim 8, wherein the rubber of the rubber matrix is natural rubber,synthetic polyisoprene rubber, styrene-butadiene rubber (SBR),styrene-isoprene-butadiene rubber, styrene-isoprene rubber,butadiene-isoprene rubber, polybutadiene, butyl rubber, neoprene,ethylene-propylene rubber, ethylene-propylene-diene rubber (EPDM),acrylonitrile-butadiene rubber (NBR), silicone rubber, thefluoroelastomers, ethylene acrylic rubber, ethylene vinyl acetatecopolymer (EVA), epichlorohydrin rubbers, chlorinated polyethylenerubbers, chlorosulfonated polyethylene rubbers, hydrogenated nitrilerubber, tetrafluoroethylene-propylene rubber, or mixtures thereof. 17.The method of claim 8, wherein the rubber of the rubber matrix is adiene homopolymer, or copolymers and terpolymers of conjugated dienemonomers with vinyl aromatic monomers and trienes, or mixtures thereof.18. A method for making a tire component comprising: mixing disk-likenanoparticles with a rubber matrix; vulcanizing the mixture; and forminga tire component from the mixture; the disk-like nanoparticles having acore layer comprising a cross-linked multi-vinyl substituted aromatichydrocarbon; a shell layer comprising tri-block copolymer chains, eachhaving a first, a second, and a third block; the first and third blockscomprising a vinyl aromatic monomer and being crosslinked with the core;the second block comprising a conjugated diene monomer and comprisingtop and bottom surfaces of the disk-like nanoparticles; the weight ratioof the monomers comprising the first block and third block to themonomers comprising the second block is 100:1 to 1:1.
 19. The method ofclaim 18, further comprising mixing, prior to the vulcanizing step, areinforcing filler selected from carbon black, silica, or both.
 20. Themethod of claim 18, wherein the rubber of the rubber matrix is a dienehomopolymer, or copolymers and terpolymers of conjugated diene monomerswith vinyl aromatic monomers and trienes, or mixtures thereof.